字符指针
#ifdef a
//每个字符插入一个空格(字符指针)
#include<stdio.h>
#include<string.h>
void InsertSpace(char input[], char tmp[]) {
    int sz = 0;
    char* point = input;
    while (*point) {
        tmp[sz++] = *point;
        point++;
        if (*point)
            tmp[sz++] = ' ';
    }
    tmp[sz] = '\0';
}
int main() {
    char* input = "hello!";
    char tmp[100] = { 0 };
    InsertSpace(input, tmp);
    puts(tmp);
    return 0;
}
#endif
